Controlling apparatus for piston pumps



F. MARTIN.

CONTROLLING APPARATUS FOR PISTON PUMPS.

APPLICATION FILED 0cT.4,1920.

1A18,95 1 a a e e une- 6, 1922.

2 SHEETSSHEET 1 F. MARTIN.

CONTROLLING APPARATUS FOR PISTON PUMPS.

APPLICATION FILED OCT. 4. 1920.

1,418,951 0 Patented June 6, 1922,

2 SHEETS-SHEET Z.

UNlTED STATES PATENT OFFICE.

FRIEDRICH MARTIN, OF ESSEN, GERMANY ASSIGNOR TO FRIED. KRUPP AKTIEN-GEELLSCHAFT, OF ESSEN-ON-THE-RUHR, GERMANY.

1&18351.

Specification of Letters Patent.

Patented June 6, 1922.

Application filed October 4, 1920. Serial No. 414,690.

To all whom it may concern:

Be it known that I, Fmnnmcrr MARTIN, residing at Essen, Germany, acitizen of the German Republic, have invented a certain new and usefulImprovement in Controlling Apparatus for Piston Pumps, of which thefollowing is a specification.

The present invention relates to regulating devices for piston pumpswith shaft drive and variable stroke-length, in which a starting orregulating piston, intended to adjust the stroke-length of the pumppiston during the operation of the pump, is influenced by the fluidpressure, generated by the pump, and also by a power sourcecounteracting said pressure; so that the fluid pressure tends to set oradjust the starting piston in the direction of a diminishedstroke-length. When the greatest piston stroke-length in pumps of knownart is selected for mean water consumption, it will be necessary to usean accumulator which delivers the additional quantity of water duringgreater water consumption. The object of the present invention is toprovide a regulating device, so that the contents of the accumulator maybe utilized to the greatest possible extent.

One embodiment of the present invention is illustrated in theaccompanying drawing, showing in Fig. 1 a side elevation, partly insection, of a regulating device, together with appurtenant parts of thepumping plant and Fig. 2 on a larger scale a similar view of means forvarying the stroke length of the pump. And this embodiment also showshow it is possible to provide a very gentle transit of the startingpiston from its position, corresponding to the greatest strokelength,into the position corresponding to a diminished water consumption; incase the water consumption is diminished from a quantity in excess ofthe greatest production of the pump to a quantity which is smaller thanthis production.

A is the casing of the piston-pump, to which suction pipe a and pressurepipe (1 are connected. The pump is provided in the usual way (Fig. 2)with several stationary cylinders A, arranged parallel to their driveshaft B. In each cylinder A is guided a plston L. which is connected bya rod Q with a cam disc R, which in turn is connected wlth the casing Aby a cross comprising two pairs of pins 1" and S, arranged at rightangles to each other. The axes of the two palrsof pins 1" and Sintersect in a point 0, formlng the center of the cross, and lying inthe axis of the shaft B. Cam disc R bears through a ball bearing T on ahearing member B, which is so adjustably mounted on a disc B rigidlyconnected with the shaft B, that it can turn relatively thereto about anaxis which stands at right angles to the axis of the shaft B in thecenter point 0 of the cross 1", S. To adjust the bearing member B, asleeve C is provided, which is slidable but not rotatable on the shaftB, driven, for example, by an electric motor of constant speed. Thesleeve C is provided on both sides of the shaft B with rack bar 0 whichengages a gear sector U. Each of the sec tors U is rotatably journalledon a bridge rigidly connected with the disc B and meshes with a gearsegment 6 mounted on the bearing member B, so that the latter can beturned relatively to the disc B rigidly connected with the shaft B. by adisplacement of the sleeve C about its axis passing through the point 0.By this displacement of the sleeve C a variation of the length of thestroke of the piston L can bebrought about in a known way, and ashortening of the length of stroke takes place when the muff C isdisplaced in the direction of the arrow w. With a stud (1' one arm ofthe bellcrank D engages a groove 0' in the muff C, the arm beingpivotally attached to the housing A of the pump. The other arm of thebell-crank D is, by means of an intermediary link E, connected with asingle-armed lever F, which is pivotally secured on the housing A. Thislever is positively connected with a piston rod H, of a starting pistonH running in a cylinder A, through the intermediary of a sliding pieceG, hinged to the lever and running in a slot in the piston rod H.

Every position of the starting piston H corresponds then with an exactposition of lcad qftnsstcumulator pist on;

the mud C, and, as a consequence, with an exact stroke-length of thepump piston. The starting or regulating piston is representedon thedrawing in a position corre- 5 spondin to the greatest stroke-length, inwhich the production of the pump is equal to the mean water consumptionin the pressure conduit." The 'dirction in which the piston H movesduring a' diminntion of the strokeinder A stands in connection with thepressure conduit a through a, pipe of, which is attadh edto"thh right'end of the cylinder,. Where the piston rod H extends. The left end ofthe cylinder A is, by means of a,

pipe J,- connected with ap-ressure tank shown) acting as powerSO'lilI'dGl" j The accumulator is provided with a-z-disk piston K,havingapiston rod on*ohe side (not rod K'- gees through; the cylinderMis connected with the'pressu'rcconduit a3, through a passage m, and at"its lower end; through J whic leads'tothev shown).

The active pressure area of the piston K,

at the' end nearest the pressure-tank,'-is denotedby R; and the smalleractivearea at trlnediary ofa pressure plate N surrounded by a cap '7???when the piston has reached within a certain small distance from thebottoinof the cylinder M, as shownby dotand-dash lines onthe drawing.When" the piston gets still closer to tlie'botto'ni" of the cylinder,the spring'beromes compressed and W tends to lift the 'iston.

In describing t e manner of" operation of the pumpin'g'plant; it will besupposed'that first the'w'ater consumption is greater than theproduction of the pump,. so that the excess water" consumption must' becompensated for by the accumulator. During the" igndition' of inertia,the accumulator piston the"springfhas be'n liberated by the collar ises" on the piston rod K.

v pressureexistingover thepiston isnow denetewi by 35, while the powersourcepressure under the piston is denoted b 39 The i ugh the length isindicated by an arrowy. The cyl and running nr'an upright -standingcylini-d. derMi At itsfup pe'r endwhere the piston.

a passe m it isconnected with thepipe' pressure) tank (not moveswithuniform'spee'd upwards after The correct fluid ower source pressure, isconsequently p F he following equation may now be written On theregulating piston H the fluid pressure now acts, in the direction ofthe-arrow y,'with' a force of a magnitude and in the opposite directionthe power A source pressure acts with a force-of the magnitude p Inopposite direction to arrow y 'a renitude As new the proportionisgreater than ft n 1n opposlte direction to arrow is always ppsltlve' andbecomes so great;

ysuitabl selection of values and thatzthe'reglp" lating'piston" H; inthe case under consid-: eration, always adjusts itself accurately-in theposition that corresponds to the greatest stroke-length. The re lat'ing.isten camnot therefore, clearly a justitsel in any position' thatrepresents a shorter stroke-length. which by longer continuation of thewater consumption in excess of-the greatestproduction of the pump,wouldcause a too' early emptying of the accumulator,

Supposing now, that the water consumption becomes less than the greatestwaterroduction'of the pump; the excess quantity" of water produced bythe pump then flows throu h the passage m in the accumulator and t episton K moves downwardly Thefluidpressure existing above the piston Kthen at first remains practically constant and the regulating piston H-is therefore:

sultan-t force consequently acts of a mag-f F consequently the resultantforce-acting.

further held in its position representing-the I greatest stroke-length.This condition remains untilthe collar -10 of the accumulator pistonStrikesthe pressure plate N, and the' piston con'sequentl reaches itsalmost 1owest position. A rther movement of the accumulator piston isnow onlyipo'ssibl'e a compression of the spring pressure above theaccumulator'piston-and in the pressure conduit must consequentlyincrease during continued compression of the spring. Finally, the force,acting in the direction of the arrow y and generated by the fluidpressure on the regulating piston H, attains an excess over the forcesacting in the opposite direction, and the regulating piston H starts nowin the direction of a shortened stroke-length of the pump.

By suitable selection of proportions and particularly by correct choiceof strength for spring P, it can be easily attained that at thebeginning of the movement of the regulating piston H, a sufiicientlygreater fraction of the excessive quantity of water enters theaccumulator, so that during the ac celeration of the regulating piston Hand the other regulating parts which are displaced by the latter, therewill be avoided, with certainty, undesirable shocks.

As soon as the regulating piston has an rived in the position whereinthe production of the pump is the same as the water consumption in thepressure conduit, the piston comes to a standstill. Then a fluidpressure will occur in the pressure conduit that lies so much above thenormal operating pressure p ,.that it equalizes the force acting uponthe regulating piston generated by the power source pressure 39Simultaneously the accumulator piston K comes to rest in its lowestposition, when the spring P is compressed so much that the springpressure and the force exerted upon the piston K by the power sourcepressure g0, equalize the force exerted by the increased fluid pressure.

If thereupon a water consumption should take place, that is in excess ofthe production of the pump corresponding to the greatest stroke-length,then the fluid pressure in the pressure conduit sinks so'that theequilibrium is broken between the force acting against the regulatingpiston H and the force acting against the accumulator piston K. Bothpistons then start to move; the regulating piston H in the oppositedirection to arrow 1 or, in other words, in a direction of an increaseof the stroke-length of the pump; and the accumulator piston K lit) inan upward direction. As soon as the accumulator piston has risen so hi11 that the collar has released the spring the correct operatingpressure p will again be obtained in the pressure conduit, through-which the force exerted by the power source pressure 1),, upon theregulating piston -H will be in excess of the forces acting in theopposite direction, as has been described hereabove.

Claims.

1. A regulation device for piston pumps with shaft drive and variablestroke-length, comprising an accumulator cylinder connected to thepressure conduit of the pump, a piston in said cylinder and means forcontrolling the fiuid pressure therein whereby the fluid pressure may beincreased when the accumulator piston has been displaced by the fluidpressure to the end of its stroke, a regulating cylinder likewiseconnected to the pressure'conduit of the pump, a piston in. saidregulating cylinder controlling the stroke-length of the pump istonduring the operation of the pump,said controlling piston being adaptedto be displaced by the fluid pressure in the direction of a diminishedstroke-length, and means whereby the controlling piston is automaticallyoperated in opposite direction, said controlling piston being soproportioned that it is held in a position correspondin to the greateststrokelength, before the uid pressure in said accumulator cylinder hasbeen increased by said fluid pressure controlling means.

2. A regulating device in accordance with claim 1, wherein the means forcontrolling the fluid pressure in the accumulator cylinder are adaptedto be actuated by the movement of the accumulator piston when near itsextreme position which corresponds to the greatest accumulator contents.

3. A regulating device in accordance with claim 1, wherein theaccumulator and the controlling piston are constructed as disk pistons,said pistons having difierent areas on both sides thereof, saidaccumulator cylinder and regulating cylinder being connected on the sideof the. greater area with a pressure tank, the proportion between thesmaller and the larger pressure areas of the accumulator piston beinggreater than that for the controllin piston.

4:: A regulating evice in accordance with claim 2, wherein theaccumulator cylinder is provided with a spring, said spring beingositioned so as to be engaged by the accumulator piston, substantiallyas and, for the. purpose .set forth.

lhe foregoing specification signed at Essen, Germany, this 17th da ofJune, 1920.

- FRIEDRIC MARTIN.

In presence of Hans Gor'rsmann, JOHANN Dnorsnns.

